1. Field of the Invention
The present invention relates to a matrix for ceramic matrix composite which contains inorganic fiber for reinforcement.
2. Related Art
A ceramic matrix composite is typical of various materials having excellent heat resistance and mechanical characteristics that have been proposed for use in the aerospace industry.
Conventional ceramic matrix composites include one composed of silicon carbide ceramic as a matrix and silicon carbide fiber as reinforcing inorganic fiber for its high heat resistance and high-temperature oxidation resistance. Composites for large-sized parts are generally produced by forming a silicon carbide matrix on fabric of silicon carbide fiber by chemical vapor infiltration (CVI), polymer impregnation and pylorysis (PIP), or a like technique.
However, where the conventional techniques are followed, pores or microcracks often remain in the silicon carbide matrix. Stress is concentrated around the pores and microcracks, and the stress cannot be transmitted sufficiently to the reinforcing fiber, resulting in reduction of the strength of the composite. Further, oxygen tends to enter through the pores or microcracks to oxidize the fiber in an elevated temperature oxidizing atmosphere, also resulting in reduction of the strength.